Data firm Cambridge Analytica accessed data from 50 million Facebook users during the 2016 US presidential campaign without the users' permission.

Facebook suspended the firm from its platform on Friday, saying Cambridge Analytica lied about deleting the unauthorized information when it was first caught in 2015.

President Donald Trump's campaign hired Cambridge to target voters and direct its political advertising strategy.

A data analysis firm linked to President Donald Trump's campaign used the personal information of 50 million people on Facebook without authorization to target them with personalized political advertisements, The Guardian reported Saturday.

The report comes just one day after Facebook suspended the firm, Cambridge Analytica, from buying ads or managing pages on the social media platform after discovering rules violations.

"We exploited Facebook to harvest millions of people's profiles. And built models to exploit what we knew about them and target their inner demons," Christopher Wylie, a former employee at Cambridge Analytica who helped the company obtain user data, told The Guardian. "That was the basis that the entire company was built on."

In 2014, Wylie reached out to Aleksandr Kogan, a Russian-American who was then a professor of psychology at the University of Cambridge in the UK. Kogan had developed a personality prediction app called "thisisyourdigitallife" that compiled personal information from people based on what they liked on Facebook.

Through his company, Global Science Research, Kogan and Cambridge Analytica paid roughly 270,000 people to download the app and take a personality test, per the Guardian report.

The demo helped Cambridge Analytica compile information not only from the users who took part in Kogan's research, but from their friends' profiles as well, exposing millions of users' data. Each person who downloaded the app only needed to have about 185 friends on Facebook for Cambridge to access the 50 million users.

Kogan's app compiled psychographic profiles of users that analyzed a variety of characteristics and personality traits, including openness, conscientiousness, agreeableness, IQ, gender, age, political views, and religion. It also evaluated people's "sensational interests," which were divided into five categories:

At the time, Kogan told Facebook he was collecting the information solely for academic purposes, but he did not reveal that his research would be handed over to Cambridge to use in political campaigns.

In a statement on Friday, Facebook said Kogan "lied to us and violated our Platform Policies by passing data from an app that was using Facebook Login to SCL/Cambridge Analytica, a firm that does political, government and military work around the globe."

'This was a scam'

Facebook reportedly first learned of Kogan's misuse of its data two years ago, but didn't disclose that fact to the public. At the time, the company removed Kogan's app from its platform and demanded that Kogan and Cambridge delete all of the data they had collected. All parties appeared to comply.

CEO of Cambridge Analytica, Alexander Nix.Pedro Nunes/ReutersIn fact, as recently as last month, Cambridge CEO Alexander Nix denied using data from Facebook and testified before a UK parliamentary committee that his firm did not have any of the data collected from Kogan's research.

But after reviewing the firm's internal emails and documents and interviewing former Cambridge employees, The New York Times found that most of the Facebook data was still in the firm's possession.

"This was a scam — and a fraud," Facebook vice president and deputy general counsel Paul Grewal told The Times. "We will take whatever steps are required to see that the data in question is deleted once and for all — and take action against all offending parties."

Facebook's statement about deleting Cambridge from its platform came late Friday night — hours before The Times broke its story on Saturday morning.

During the 2016 US presidential race, Cambridge performed a variety of tasks for the Trump campaign, including profiling voters, purchasing TV ads, and suggesting where Trump should travel to best appeal to voters, according to The Times.

Several news outlets reported in 2016 that the Trump campaign paid Cambridge Analytica $5 million for its services in September alone that year, a significant increase from the $250,000 it paid one month earlier.

But the extent to which the Trump campaign relied on the firm's work and whether its services helped Trump win aren't exactly clear.

Cambridge Analytica was founded in 2013. Shortly thereafter, prominent Trump supporter and American businessman Robert Mercer invested $15 million in the firm. Steve Bannon, Trump's former chief strategist, served as board member.

In addition to its involvement with the Trump team, Cambridge has also been involved with dozens of other political campaigns in the US and the UK, including the Brexit referendum and Sen. Ted Cruz's primary run in 2016.